The present invention relates to a fundus measuring apparatus for measuring a three-dimensional configuration of the fundus (fundus) on the basis of stereoscopic images of the fundus as well as a recording medium with a fundus measurement program recorded thereon.
It is said that the observation of the optic disc (hereafter simply referred to as the disc) through an image of the fundus is important as the diagnosis of glaucoma which is known as one of disorders in the visual function. In recent years, apparatuses have been proposed in which a three-dimensional configuration of the fundus is measured on the basis of stereoscopic images of the fundus photographed by a stereoscopic fundus camera, and the cup of the disc and a peripheral portion of the disc are analyzed quantitatively.
The method of measuring the three-dimensional information of the fundus on the basis of stereoscopic images of the fundus is generally known as a stereoscopic matching method, and in obtaining height information it is important to extract corresponding spots (corresponding points) in left and right images. To accurately effect the extraction of corresponding spots, it is necessary to determine an amount of deviation (hereafter referred to as the parallax) of the overall image due to an refractive error of the photographed eye, to thereby cause the left image and the right image to correspond to each other. Conventionally, the parallax is determined on the basis of a characteristic point such as a branching point of a blood vessel or the like on the fundus to cause the left and right images to correspond to each other.
However, there are cases where the contrast in the photographed stereoscopic images of the fundus is not good, and if a branching point of the blood vessel is unclear, the accuracy in correspondence between the left and right images is often poor, often making the measurement impossible. In addition, since the measurement of the parallax based on the branching point of the blood vessel relies on two-dimensional measurement, there has been a problem in that a long processing time is required.
Still further, the extraction of corresponding spots from the left and right images causes a problem in which the overall processing time is long, since to search for pixels (region) which are best in conformity with specific pixels (specific region) of one image, the other image must be searched minutely over a certain range.